1. Technical Field of the Invention
The present invention relates generally to vehicle speed control systems, and more particularly to a vehicle speed control system which, in response to a manual operation of a driver, automatically controls the speed of a vehicle such that it follows a preceding vehicle at a constant interval.
2. Background Art
Japanese Patent First Publication No. 60-121130 discloses a vehicle speed control system capable of modifying an inter-vehicle distance from a preceding vehicle detected using a radar unit, for example. This conventional vehicle speed control system maintains a current vehicle speed even when the detected preceding vehicle has disappeared. In addition, another system known in the art is capable of accelerating a controlled vehicle to a set speed value when the system has lost a detected preceding vehicle.
The drawback of such a prior art vehicle speed control system is that when a preceding vehicle is traveling at a slow speed in a front detection area and the system cannot detect it for any reason, such as a failed preceding vehicle detecting sensor, for example the speed of the controlled vehicle is undesirably brought under cruise control independent of constant inter-vehicle distance control.